The human heart relies on a series of one-way valves to help control the flow of blood through the chambers of the heart. Deoxygenated blood returns to the heart, via the superior vena cava and the inferior vena cava, entering the right atrium. The heart muscle tissue contracts in a rhythmic, coordinated heartbeat, first with an atrial contraction which aids blood in the right atrium to pass through the tricuspid valve and into the right ventricle. Following atrial contraction, ventricular contraction occurs and the tricuspid valve closes. Ventricular contraction is stronger than atrial contraction, assisting blood flow through the pulmonic valve, out of the heart via the pulmonary artery, and to the lungs for oxygenation. Following the ventricular contraction, the pulmonic valve closes, preventing the backwards flow of blood from the pulmonary artery into the heart.
Oxygenated blood returns to the heart, via the pulmonary veins, entering the left atrium. Left atrial contraction assists blood in the left atrium to pass through the mitral valve and into the left ventricle. Following the atrial contraction, ensuing ventricular contraction causes mitral valve closure, and pushes oxygenated blood from the left ventricle through the aortic valve and into the aorta where it then circulates throughout the body. Under nominal conditions, prolapse of the mitral valve is prevented during ventricular contraction by chordae attached between the mitral valve leaflets and papillary muscles located in the left ventricle. Following left ventricular contraction, the aortic valve closes, preventing the backwards flow of blood from the aorta into the heart.
Unfortunately, one or more of a person's heart valves can have or develop problems which adversely affect the valves' function and, consequently, negatively impact the person's health. Generally, problems with heart valves can be organized into two categories: regurgitation and/or stenosis. Regurgitation occurs if a heart valve does not seal tightly, thereby allowing blood to flow back into a chamber rather than advancing through and out of the heart. This can cause the heart to work harder to remain an effective pump. Regurgitation is frequently observed when the mitral valve fails to properly close during a ventricular contraction. Mitral regurgitation can be caused by chordae stretching, tearing, or rupturing, along with other structural changes within the heart.
Neochordal replacement for stretched or torn chordae is one option to reduce regurgitation. In such a procedure, chords to be replaced are identified and dissected as required. A papillary suture is placed in a papillary muscle corresponding to the dissected chord. The papillary suture may optionally be pledgeted on one or both sides of the papillary muscle. A leaflet suture is also placed in the corresponding mitral valve leaflet. The papillary suture and the leaflet suture may then be tied or otherwise fastened together to create a replacement chord to help support the mitral valve leaflet and prevent regurgitation.
Unfortunately, while the above techniques are proven methods of heart valve repair, technical challenges impede their widespread utilization, especially in minimally invasive cardiac surgery. While minimally invasive surgery can dramatically reduce patient recovery times by avoiding the need for full or partial sternotomy, it is difficult and time consuming to manipulate a suture needle with forceps through a minimally invasive opening between adjacent ribs to place the sutures for neochordal replacement. An innovative system that remotely delivers and reliably places suture for minimally invasive neochordal replacement would be highly desirable.